Two weeks ago I was fishing the Little J above Spruce Creek. The air temperature reached the upper 70s, the night time temperature was in the mid 60's. I was surprised to see that by 4 p.m., the water temperature was about 69 degrees... borderline for me. I was ready to pack it in after temping the water when I noticed across the river a young man hooked a nice fish. He fought it for over 5 minutes, netted it walked it up the bank to show a group of older anglers. Measurements were taken. (Heard one man say "21 inches, nice!") Pictures were taken, handshakes were exchanged... the whole time the fish was out of water... I'm thinking, "That fish is DOA." Sure enough, he tried to revive it but after 15 minutes it was still rolling on its side... I left and he was still working on the fish in faster water. I decided to lower my limit to 68 degrees.

Posted on: 2010/7/1 12:05

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"I used to like fishing because I thought it had some larger significance. Now I like fishing because it's the one thing I can think of that probably doesn't." --John Gierach

I think if you pull a trout out of water after 5 minutes of struggle, then keep it out of water for another minute or more, you are going to have a dead fish even if the water temperatures were in the mid-50s.

Posted on: 2010/7/1 12:19

_________________I am so clever that sometimes I don't understand a single word of what I am saying.

Agreed. Nomatter what the temperature, if you have a fish out of water for too long as described, especially after a 5 minute fight, then water temperature is not the reason that its going to die.

Anytime you need to "revive" a fish is a bad sign. The fish may seem as if its revived, and swim off looking apparantly fine. But there's a good chance that fish is going to die from acidosis within a few days.

Biologically speaking, trout are similar to humans in their metabolism. Muscles need energy to move, which is usually supplied by aerobic metabolism (requires oxygen and sugar to create energy). But we have systems for anabolic metabolism too. This occurs when there is not enough oxygen, either from lack of actual oxygen available or strenuous exercise which exceeds the heart and arteries' ability to transport oxygen to the muscle. Anabolic metabolism does supply the energy required to do the job, however a side effect is hydrogen ions being produced, which lower the pH, i.e. acidosis. It's why we get sore muscles, for instance. And like sore muscles, the peak effects are often a day or so later. And in order to recover, you must consume more oxygen at rest than is otherwise typical.

All the same is true in fish. If we have an extended fight, the fish is undergoing anabolic metabolism to supply its energy, and moreso if the water is warm and the available oxygen low. Holding it out of the water requires more anabolic metabolism just to keep the fish's organs functioning. And upon release, that fish needs more oxygen to survive than it did prior to being hooked. If that oxygen isn't available, more anabolic metabolism will take place, until the blood is acidic enough to kill some of the organs in the fish and the fish dies.

Bottom line: The warmer the water, the shorter the fight and quicker the release must be for the fish to survive. In water that remains above 70 degrees for any length of time, there is very little leeway for any fight or release to take place, and the fish is unlikely to recover due to lack of oxygen in the hours and days AFTER the fight. Just because it looks fine when it swims away does not mean it will live. But if that same fish swims away fine in the warmer water, and the water overnight cools to more comfortable levels, enough oxygen may be available for the fish to rest and recover from its ordeal.

Thanks for all of the input. This discussion has been helpful. I always try to handle the fish as little as possible and bring it to hand as efficiently as possible but just wanted to make sure that I am being responsible. The purpose of the post was really to see if there were general guidelines and I think that I have some basic ones that will help me to judge the specific situations that I find myself in.

So, if I can summarize, my takeaways are:

1) Get a thermometer for the vest2) If I am fishing for trout during the hot months try to do it first thing in the am or in the evening, minimize fight time and release ASAP3) Be careful if the temp is creeping toward 704) If its higher than 70 pretty much stand down on the trout and fish for smallies

I think that deciding to fish a certain tactic before you get to the stream is a recipe for disappointment.

I fish dries if they're rising, wets if they're on emergers, streamers if the flows are good, and nymph otherwise. I've found a place for all four when the water is warmer. It depends on other factors.

Pretty much. I'll make the point that all waters are not the same temperature. If the water you're on is higher than 70, do stand down on the trout. You can choose to go for smallies, and thats a great option. But if your set on trout, there are other streams, and the stream one valley over might be only 60 degrees. In time, you learn which ones warm and which ones stay cool, and can fairly reliably guess at the temperatures on a number of streams based on the one you're on.

As for tactics, there's a slight correlation between dry fly activity and warmer water. Part of that is just water level, warmer water often coincides with lower water and dries often work in low water. But even besides that, trout tend to rise much more commonly when water is northwards of 60 degrees or so (there are plenty of exceptions to this, though).

I commonly go with an initial plan, like trying to time a specific hatch, to high muddy water with black streamers, or to freshly stocked rainbows with egg patterns, etc. But I do agree with Jay, it is vitally important to adjust to the conditions in front of you. Be willing to throw out that plan at the drop of a hat. Even the best of us sometimes make the mistake of stubbornly sticking to a plan that isn't working out. For instance, if you're after a hatch and even manage to time it right, but the fish are on something different, well, give it up and listen to the fish!

Yep, the shorter the fight the better. Use as heavy a tippet as you can get away with for the conditions, but not heavier. :) Fight them as quickly as possible given the tippet strength chosen. Handle as little as possible and return them to the stream as quickly as possible. Nets can often shorten the fight a bit, especially on larger fish.

I don't advocate purposely going to a stream to fish while knowing that the temperatures are in the 70s. In fact, with any reasonable alternative, I would find another creek. But if I fish all morning and into the afternoon with water temps in the mid or even upper 60s and at 4:30 PM they peak at 70, I will not leave the stream on that account alone, nor will I accept the idea that any fish I catch or even many of the fish I catch from that point onward are as good as dead. It just isn't true.

Posted on: 2010/7/1 16:03

_________________I am so clever that sometimes I don't understand a single word of what I am saying.

Meh? No comprende. I think it is good to warn people about the potential risk as temperatures rise, but not to overstate it either. Then it seems more like a scare tactic than reliable information, and you know how that has turned out for establishing other ethics. I usually know the first fish I catch how the water temperatures have effected them. If its fight is short, non-existent or weak, I become suspicious. It is no fun to catch lethargic fish, except maybe steelhead or salmon.

The upper lethal limit for brook, brown and rainbow are only a few degrees apart, I think 75-77 degrees or so. From what I have read, browns and rainbow are more or less equivalent, despite popular statements to the contrary. Of course, different local strains may make one superior to the other. Brookies are consistently reported lower, but by only a degree or so. Again, I imagine local variations occur.

The Upper Lethal Limit reflects the water temperature at which, if sustained for 24/48 hours (can't remember exact, but assume 24), the fish will die. At temperatures below that they certainly experience thermal stress. Their bodies are not designed to withstand heat even though they are cold-blooded. To protect the organs and other tissues, a chemical substance is released in the bloodstream. If sustained, this becomes lethal. I'm not sure if this is the same substance pcray expounds on, but you'll find the concept in the literature.

If you have the luxury, in any sense, to fish for trout only when there is little chance of incidental mortality, then asside from applying the most stringent landing and handling practices, never fish for trout above 70 or if the temperatures overnight do not drop into at least the mid-sixties. Beyond that is a matter of degrees until you hit the lethal limit, which depends upon no other factors, such as general trout health, dissolved oxygen, and fight and handling practices. Seen another way, the ULL can be effectively driven downward by any of these stressors.

Posted on: 2010/7/1 22:32

_________________I am so clever that sometimes I don't understand a single word of what I am saying.

Above 68 degrees troout have a hard time with their metabolism so it's best not to fish for them when the water is that warm or warmer. But many trout streams can be fished at daybreak with little impact if you know the stream.As for limestone streams long hot spells do warm the limestone streams into the seventies so always check the water temperatures during heat waves.If the trout act stressed they probably are. If you see several pools where fish are gathered and not moving much they are probably stressed, if they are holding at the mouth of a stream, they are probably stressed, if it's hot and there is a hatch in progress and the fish aren't feeding, they are pobably stressed.This of course only applies to wild trout, if you want to fish a stocked stream catch all you can and take the limit home, they will die anyway.When taking a temperature of a stream take it on the bottomas I always do, not at the surface. Take the temp at around 6 in the evening that will give you an idea of the highest temp during the day, taking the temp in the morning only tells you that a stream is cold during the early hours of the day, it may get too warm to even hold trout during the summer.

Posted on: 2010/7/2 17:43

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The object of a resource is to use and reuse a resource, not to use it up, have we learned nothing in over 125 years of stocking?